Membrane plasmapheresis utilizes a porous membrane, for example one made of polysulfone resin, which permits the extraction of plasma by diffusion through the membrane while preventing passage of the blood cells. For example, Brown et al, U.S. patent application Ser. No. 140,111, filed Apr. 14, 1980, discloses a current commercial membrane plasmapheresis apparatus.
Generally, the membrane plasmapheresis apparatus will include a "hardware" portion, with pumps, brackets for holding blood flow tubing, and other necessary apparatus as illustrated, for instance, by the above-described patent application.
Typically, membrane plasmapheresis devices utilize a disposable plasmapheresis module carried by the "hardware", which module contains the plasmapheresis membrane positioned within a housing to define the first and second flow paths on opposite sides of the membrane respectively, for blood flow and for collected plasma flow. The module will then be connected to disposable tubing and other blood contacting components, all of which are generally replaced after each plasmapheresis operation.
In accordance with this invention, a design of semipermeable membrane diffusion device is provided which is particularly used with advantage as a membrane plasmapheresis module, although it may be utilized in other forms of semipermeable membrane diffusion as desired, for example for blood oxygenation, or dialysis either for blood or other materials. Advantages of reliable sealing coupled with simplicity are provided by this invention for improvement in both the reliability, simplicity, and consequently the cost of membrane diffusion devices, and particularly the specially contemplated membrane plasmapheresis module.